To produce tyres with reduced rolling resistance, a number of proposed solutions have been worked out. In DE-A 2 255 577 and 4 435 311, EP-A 670 347 and U.S. Pat. No. 4,709,065, specific polysulfidic silanes have been described as reinforcing fillers for silica-containing rubber vulcanisates. A disadvantage of the use of the polysulfidic silanes described there as reinforcing fillers for silica-containing rubber vulcanisates, however, is that relatively large quantities of the expensive polysulfidic silanes are needed to achieve acceptable processing properties.
To improve the processing properties of silica-containing rubber mixtures, other additives such as fatty acid esters, fatty acid salts or mineral oils have been proposed. However, these additives have the disadvantage of increasing flowability but, at the same time, reducing the moduli at greater elongation (e.g. 100 to 300%), so that the reinforcing effect of the filler is reduced.
In addition, it was known to add polyalcohols and polyglycols to rubber mixtures to improve their processing properties (cf. EP-A 761 734 and EP-A 738 755). Compared with the distillation residues from industrial trimethylolpropane production according to the invention, however, polyalcohols and polyglycols are expensive and inadequate in terms of improving flowability and scorch time.